1. Field of the Invention
The present invention is directed to large size umbrellas, in particular umbrellas of the type having a canopy supported by a post.
2. Description of Related Art
Heretofore, large umbrellas, such as patio umbrellas, had been configured to allow the shade or canopy (e.g., comprising a fabric panel supported by rib frame structure) to be tilted at different angular positions or orientations with respect to a generally vertical support post. By being able to reposition the orientation of the canopy to the post, better coverage of the canopy can be achieved, to better shade the user from the sun (e.g., at different times of the day).
U.S. Pat. No. 6,014,980 to Glatz discloses a free-arm canopy having a side arm cantilevered from a vertical support post, and a canopy hanging from the extended end of the extended side arm. The side arm is rotatable about its axis. However, the Glatz free-arm canopy involves a rather complicated combination of structures to implement movement including rotation of the side arm to change the orientation of the canopy with respect to the support post. A combination of steps are required to manipulate a combination of structures in order to change the orientation of the canopy with respect to a fixed support post. In particular, the long extending side arm that supports the canopy needs to be rotated in order to change the orientation of the canopy. Given the canopy includes a metal frame and heavy fabric material, and the canopy extends from the end of the side arm, the weight of the canopy creates a rather heavy load to be maneuvered by the rotation of the side arm. As can be appreciated, the structure disclosed in the Glatz patent provides poor mechanical leverage for the rotation of the side arm to maneuver the dead weight of the canopy extending at the extended end of the side arm. Consequently, significant effort is required of the user in rotating the long side arm in order to tilt the load of the canopy hanging from the extended end of the side arm. In addition, given the rotation of the side arm, the degree of freedom of orientation of the canopy is limited to an arc about the side arm axis. Further, given the requirement of a rope that runs through the side arm for use to open/close the canopy, range of rotation of the side arm is therefore limited, thus limiting the range of orientations of the canopy. The degree of freedom of orientation of the canopy is thus severely limited.
For example, U.S. Pat. No. 6,840,253 to Ma, the inventor of the present invention, discloses a “side post umbrella” that includes a side arm supported by and cantilevered from a side support post. A shade hangs from the extended end of the side arm. The side arm is rotatable about its axis, thus tilting the shade to change its orientation with respect to the support post. A handle is provided at the supported end of the side arm, which provides improved leverage for the user to rotate the side arm.
There is a further need for a simple, reliable and easy to operate structure that provides better maneuverability and additional degrees of freedom of orientation of the canopy with respect to a support.